Universal joint dustproof structure and mounting method

Abstract

The invention relates to the technical field of universal joints, in particular to a universal joint dustproof structure and an installation method. The universal joint dustproof structure comprises a cross shaft assembly and a dustproof assembly, wherein the cross shaft assembly comprises a cross shaft unit and a shaft neck unit; the shaft sleeve assembly is arranged on the peripheral wall of the shaft neck unit in a sleeving manner; the dustproof assembly comprises a first dustproof unit, a second dustproof unit and a third dustproof unit which are sequentially and integrally formed in the axial direction of the journal unit; the first dustproof unit sleeves the peripheral wall of the shaft sleeve assembly and is in clearance fit with the shaft sleeve assembly; the third dustproof unit abuts against the cross shaft unit in the axial direction of the shaft neck unit and is in interference fit with the shaft neck unit in the circumferential direction of the shaft neck unit. A rolling assembly; the sealing assembly is located in the containing cavity; wherein the second dustproof unit is in clearance fit with the sealing assembly; part of the second dustproof unit abuts against the shaft sleeve assembly. Therefore, the problem that the universal joint dust cover is bent and fractured is solved.

Description

Technical Field

[0001] This invention relates to the field of universal joint technology, and more specifically, to a dustproof structure and installation method for a universal joint. Background Technology

[0002] In the field of universal joint drives, to prevent external dust and impurities from entering the internal rolling components (such as needle roller bearings) and to prevent leakage of internal lubricating grease, a dedicated dustproof structure is usually required. In existing technologies, such as... Figure 1 As shown, a common solution is to use a U-shaped dust cover. The open end of the dust cover is fixed to the bushing by clamps or other means, and its bottom is fitted and sealed to the journal of the cross shaft.

[0003] Existing technologies offer various improvements to the sealing effect by adding sealing lips, altering contact methods, or adding auxiliary components. However, these existing technologies, particularly the traditional U-shaped dust cover structure, exhibit significant drawbacks in practical applications and production. Firstly, during installation, the abrupt change in structure at the bottom bend of the U-shaped structure leads to stress concentration, making it highly susceptible to undesirable bending deformation or even breakage, resulting in premature failure of the dust cover. To address this structural strength issue, the industry is often forced to embed an iron frame within the dust cover to enhance its rigidity, but this undoubtedly increases material costs and manufacturing complexity. Secondly, even with the added frame, the sealing mechanism between the U-shaped dust cover and adjacent components (such as bushings and journals) still has room for optimization, and its overall dustproof sealing effect and reliability still need improvement. Therefore, there is an urgent need for a universal joint dust cover structure that boasts high structural strength, ease of manufacturing, and superior sealing performance. Summary of the Invention

[0004] To address the problem of bending and breakage of universal joint dust covers, this invention provides a universal joint dust cover structure and installation method.

[0005] In a first aspect, the present invention provides a universal joint dustproof structure, comprising:

[0006] A cross shaft assembly includes a cross shaft unit and a journal unit connected to the cross shaft unit;

[0007] A bushing assembly is fitted onto the outer peripheral wall of the journal unit;

[0008] A dustproof assembly includes a first dustproof unit, a second dustproof unit, and a third dustproof unit integrally formed sequentially along the axial direction of a journal unit; the inner peripheral walls of the first and second dustproof units, together with the outer peripheral wall of the journal unit and the inner peripheral wall of the bushing assembly, form a receiving cavity; the first dustproof unit is sleeved on the outer peripheral wall of the bushing assembly and has a clearance fit with the bushing assembly; the third dustproof unit is sleeved on the outer peripheral wall of the journal unit; the third dustproof unit abuts against the cross shaft unit along the axial direction of the journal unit and has an interference fit with the journal unit along the circumferential direction of the journal unit;

[0009] A rolling assembly is located within the receiving cavity; the rolling assembly is tactilely positioned between the journal unit and the bushing assembly.

[0010] A sealing assembly is located within the receiving cavity; the sealing assembly is sleeved on the outer peripheral wall of the journal unit; wherein, the second dustproof unit is clearance-fitted with the sealing assembly; a portion of the second dustproof unit abuts against the bushing assembly.

[0011] In some embodiments, the sealing assembly includes a sealing unit and a skeleton unit; the sealing unit is sleeved on the outer peripheral wall of the journal unit; the inner peripheral wall of the skeleton unit is connected to the sealing unit along the circumferential direction of the journal unit; a portion of the outer peripheral wall of the skeleton unit is connected to the bushing assembly along the circumferential direction of the journal unit; and another portion of the outer peripheral wall of the skeleton unit is clearance-fitted with the second dustproof unit along the circumferential direction of the journal unit.

[0012] In some embodiments, the skeleton unit includes an integrally formed first skeleton portion and a second skeleton portion; the outer peripheral wall of the first skeleton portion is clearance-fitted with a portion of the second dustproof unit; the inner peripheral wall of the first skeleton portion is connected to a portion of the sealing unit; the outer peripheral wall of the second skeleton portion is connected to a bushing assembly; and the inner peripheral wall of the second skeleton portion is connected to another portion of the sealing unit.

[0013] In some embodiments, the second dustproof unit includes an integrally formed main body and a protrusion; the main body is connected to the first dustproof unit and the third dustproof unit along the axial direction of the journal unit; the protrusion extends along the main body toward the axial direction of the journal unit; wherein the protrusion has an inclined first protruding inner wall and a second protruding inner wall, and an acute angle is formed between the first protruding inner wall and the second protruding inner wall toward the axial direction of the journal unit; the inner peripheral wall of the main body and the first protruding inner wall are clearance-fitted with the outer peripheral wall of the first frame portion; the second protruding inner wall abuts against the bushing assembly.

[0014] In some embodiments, the bushing assembly includes a bushing unit; the bushing unit is sleeved on the journal unit, and the bushing unit has an interconnected mounting groove and a chamfered groove along the circumference of the journal unit; a first dustproof unit is clearance-fitted with the bushing assembly in the mounting groove; a protrusion extends into the chamfered groove; and a second protruding inner wall at least partially abuts against the bushing assembly in the chamfered groove.

[0015] In some embodiments, the thickness of the first dustproof unit is less than the thickness of the third dustproof unit.

[0016] In some embodiments, the outer peripheral wall of the first dustproof unit has a groove.

[0017] In some embodiments, the clearance between the first dustproof unit and the bushing assembly in the mounting groove is greater than or equal to the clearance between the inner peripheral wall of the main body and the outer peripheral wall of the first protruding inner wall and the first skeleton part.

[0018] In some embodiments, the journal unit includes a first journal and a second journal having the same axis and connected in sequence; the circumference of the first journal is greater than the circumference of the second journal; a third dustproof unit abuts against the cross shaft unit along the axial direction of the journal unit and is at least partially press-fitted with the first journal along the circumferential direction of the journal unit; a sealing unit is sleeved on the outer peripheral wall of the second journal.

[0019] Secondly, the present invention provides a method for installing a universal joint dustproof structure, which is applied to any of the universal joint dustproof structures described in the first aspect, and includes the following steps:

[0020] The rolling component is installed inside the bushing assembly;

[0021] Install the sealing assembly inside the bushing assembly to initially seal the rolling assembly;

[0022] The dustproof assembly is installed on the bushing assembly and the sealing assembly to form a mounting cavity;

[0023] The cross shaft assembly is installed into the mounting cavity; wherein, the first dustproof unit is clearance-fitted with the bushing assembly; the third dustproof unit abuts against the cross shaft unit and is interference-fitted with the journal unit; a portion of the second dustproof unit is clearance-fitted with the sealing assembly, and at least a portion of the second dustproof unit abuts against the bushing assembly; wherein, the dustproof assembly includes an integrally formed first dustproof unit, second dustproof unit, and third dustproof unit; the two ends of the second dustproof unit are respectively connected to the first dustproof unit and the third dustproof unit.

[0024] To solve the problem of bending and breakage of the universal joint dust cover, the present invention has the following advantages:

[0025] By designing the dustproof components as first, second, and third dustproof units integrally formed along the axial direction of the journal unit, the overall structural strength and deformation resistance of the dustproof cover are significantly improved. This effectively avoids the problem of traditional U-shaped dustproof covers being easily damaged due to stress concentration at the bends, while also simplifying the structure and reducing manufacturing costs. The third dustproof unit, on the one hand, abuts against the cross shaft unit axially, achieving the first axial seal against foreign object intrusion; on the other hand, its circumferential fit with the journal unit provides not only a reliable radial seal but also applies a preload to the entire dustproof assembly after installation. This preload causes the clearance fit between the first dustproof unit and the bushing assembly to adaptively tend towards a better sealing state, thereby greatly improving the dustproof effect at this dynamic seal while ensuring the flexible rotation of the bushing assembly. The second dustproof unit abuts against the bushing assembly, providing a stable support point for the entire dustproof assembly, making the transmission of the aforementioned preload and the optimization adjustment of the clearance more effective and controllable. At the same time, its clearance fit with the sealing assembly cleverly avoids unnecessary friction and wear between the two during universal joint operation, ensuring the independent sealing performance of the sealing assembly and extending the service life of each component. The receiving cavity formed by the first and second dustproof units, the journal, and the bushing provides a sealed working space with multiple seals protecting the rolling assembly and the sealing assembly, comprehensively achieving the goals of high strength, long service life, and high reliability of the dustproof structure. Attached Figure Description

[0026] Figure 1 A schematic diagram of a universal joint dustproof structure in the prior art is shown;

[0027] Figure 2 A schematic diagram of a universal joint dustproof structure according to one embodiment is shown;

[0028] Figure 3 A partial schematic diagram of a universal joint dustproof structure according to one embodiment is shown;

[0029] Figure 4 A cross-sectional view of a dustproof component in a universal joint dustproof structure according to one embodiment is shown.

[0030] Figure label:

[0031] In the figure, 01 is a U-shaped dust cover; 10 is a cross shaft assembly; 11 is a cross shaft unit; 12 is a journal unit; 121 is a first journal; 122 is a second journal; 20 is a bushing assembly; 21 is a bushing unit; 22 is a mounting groove; 23 is a chamfered groove; 30 is a rolling assembly; 40 is a sealing assembly; 41 is a sealing unit; 42 is a skeleton unit; 421 is a first skeleton part; 422 is a second skeleton part; 50 is a dustproof assembly; 51 is a first dustproof unit; 52 is a second dustproof unit; 521 is a main body part; 522 is a protrusion; 5221 is a first protruding inner wall; 5222 is a second protruding inner wall; 53 is a third dustproof unit; and 54 is a groove. Detailed Implementation

[0032] The invention will now be discussed with reference to several exemplary embodiments. It should be understood that these embodiments are described merely to enable those skilled in the art to better understand and thus implement the invention, and are not intended to imply any limitation on the scope of the invention.

[0033] As used herein, the term "comprising" and its variations are to be interpreted as open-ended terms meaning "including but not limited to". The term "based on" is to be interpreted as "at least partially based on". The terms "one embodiment" and "an embodiment" are to be interpreted as "at least one embodiment". The term "another embodiment" is to be interpreted as "at least one other embodiment". The terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "vertical", "horizontal", "lateral", "longitudinal", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. These terms are primarily for the purpose of better describing the invention and its embodiments and are not intended to limit the indicated devices, elements, or components to having a specific orientation or to be constructed and operated in a specific orientation. Furthermore, some of the above terms may be used to indicate other meanings besides orientations or positional relationships; for example, the term "upper" may in some cases indicate a dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this invention according to the specific circumstances. In addition, the terms "installed", "set", "equipped with", "connected", and "linked" should be interpreted broadly. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, elements, or components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. Furthermore, the terms "first," "second," etc., are mainly used to distinguish different devices, elements, or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance or quantity of the indicated devices, elements, or components. Unless otherwise stated, "a plurality of" means two or more.

[0034] In the field of universal joint transmissions, to prevent the intrusion of external contaminants and leakage of internal lubricant, such as Figure 1 As shown, a U-shaped dust cover 01 is typically used, with its open end fixed to the bushing by a clamp, and its bottom sealed to the cross shaft journal. However, the traditional U-shaped structure suffers from significant stress concentration at the bend in the bottom of the dust cover due to structural abrupt changes, leading to fatigue cracks or even fractures and premature failure. Even with the addition of a frame, the sealing method between the dust cover and components such as the bushing and journal remains insufficient, and the overall reliability and durability of the dust seal need to be improved. Therefore, there is an urgent need for a dustproof solution that combines high strength, simple structure, and excellent sealing performance to overcome the shortcomings of existing technologies.

[0035] Example 1:

[0036] In this embodiment, as Figure 2As shown, a universal joint dustproof structure includes: a cross shaft assembly 10, including a cross shaft unit 11 and a journal unit 12 connected to the cross shaft unit 11;

[0037] The bushing assembly 20 is fitted onto the outer peripheral wall of the journal unit 12;

[0038] The dustproof assembly 50 includes a first dustproof unit 51, a second dustproof unit 52, and a third dustproof unit 53 integrally formed sequentially along the axial direction of the journal unit 12. This integral design fundamentally solves the defects of stress concentration and easy breakage at bending points in traditional U-shaped dust covers 01, significantly improving the overall structural strength and reliability of the dust cover. Furthermore, it eliminates the need for an internal metal frame, simplifying the structure and reducing manufacturing costs. The inner peripheral walls of the first dustproof unit 51 and the second dustproof unit 52, together with the outer peripheral wall of the journal unit 12 and the inner peripheral wall of the bushing assembly 20, form a receiving cavity. This design provides a multi-layered, sealed working space for the rolling assembly 30 and the sealing assembly 40. The first dustproof unit 51 is sleeved on the outer peripheral wall of the bushing assembly 20 and... The first dustproof unit 51 and the bushing assembly 20 are fitted with a clearance fit; this clearance fit is the key to ensuring that the bushing assembly 20 can rotate flexibly; the third dustproof unit 53 is sleeved on the outer peripheral wall of the journal unit 12; the third dustproof unit 53 abuts against the cross shaft unit 11 along the axial direction of the journal unit 12 and is interference-fitted with the journal unit 12 along the circumferential direction of the journal unit 12; this interference fit not only provides radial sealing for the cross shaft unit 11 to prevent foreign objects from entering from here, but also applies an axial preload to the entire dustproof assembly 50 after installation. Under the action of this preload, the gap between the first dustproof unit 51 and the bushing assembly 20 will adaptively tend to a better sealing state (i.e., the gap is reduced), thereby greatly improving the dustproof effect of this dynamic sealing interface while maintaining the rotation function;

[0039] The rolling assembly 30 is located within the receiving cavity; the rolling assembly 30 is rotatably disposed between the journal unit 12 and the bushing assembly 20.

[0040] The sealing assembly 40 is located within the receiving cavity; the sealing assembly 40 is sleeved on the outer peripheral wall of the journal unit 12; wherein, the second dustproof unit 52 is clearance-fitted with the sealing assembly 40; the clearance design between the second dustproof unit 52 and the sealing assembly 40 cleverly avoids interference and frictional wear between the dustproof assembly 50 and the sealing assembly 40, which serves as the main seal, during operation, thus ensuring both the independent working efficiency and lifespan of the sealing assembly 40, and ensuring that the function of the dustproof assembly 50 as an external protective cover is not affected; part of the second dustproof unit 52 abuts against the bushing assembly 20; the abutment provides a crucial intermediate support point for the entire dustproof assembly 50, which allows the preload generated by the third dustproof unit 53 to be effectively transmitted and distributed, ensuring that the process of optimizing the clearance of the first dustproof unit 51 is more stable and controllable.

[0041] This invention constructs a multi-layered sealing and protection system that combines rigidity and flexibility, and dynamic and static elements, through the ingenious connection and cooperation of each unit, effectively improving the dustproof sealing performance and service life of the universal joint under harsh working conditions.

[0042] In this embodiment, as Figure 3 As shown, the sealing assembly 40 includes a sealing unit 41 and a skeleton unit 42. The sealing unit 41 is sleeved on the outer peripheral wall of the journal unit 12. Its function is to achieve close contact with the rotating surface of the journal unit 12, forming the most important and core radial dynamic sealing barrier to prevent grease leakage in the cavity. The inner peripheral wall of the skeleton unit 42 is connected to the sealing unit 41 along the circumference of the journal unit 12. This connection allows the skeleton unit 42 to provide solid radial support and reliable shape retention for the relatively soft sealing unit 41, effectively preventing permanent deformation or twisting of the sealing unit 41 during long-term use or under pressure, thereby ensuring the durability and stability of its sealing effect. Part of the outer peripheral wall of the skeleton unit 42 is connected to the journal unit 12 along the circumference of the journal unit 12. The connection between the sleeve assembly 20 and the skeleton unit 42 and the bushing assembly 20 stably positions the entire sealing assembly 40 within the bushing assembly 20, preventing circumferential or axial movement during operation and providing a stable working foundation for the sealing unit 41. The outer peripheral wall of another part of the skeleton unit 42 is clearance-fitted with the second dustproof unit 52 along the circumference of the journal unit 12. This clearance fit ensures that there is no rigid connection or friction between the sealing assembly 40 (as the main seal) and the dustproof assembly 50 (as the external dustproof unit). This not only achieves functional decoupling—allowing the main seal to focus on sealing oil and the dustproof cover to focus on dust prevention—but also greatly reduces the risk of wear between the two, extends the service life of each component, and jointly improves the reliability of the universal joint drive assembly.

[0043] In this embodiment, as Figure 3As shown, the skeleton unit 42 includes an integrally formed first skeleton part 421 and a second skeleton part 422; the outer peripheral wall of the first skeleton part 421 is clearance-fitted with a portion of the second dustproof unit 52; the first skeleton part 421 serves as a dedicated isolation and mating interface, precisely maintaining the non-contact state between the main sealing assembly 40 and the external dustproof assembly 50, effectively eliminating friction and wear between the two, and ensuring the independence and long-term effectiveness of their respective functions; the inner peripheral wall of the first skeleton part 421 is connected to a portion of the sealing unit 41; this connection allows the first skeleton part 421 to provide local and precise radial support for the corresponding part of the sealing unit 41, preventing excessive deformation of the sealing lip under pressure, thereby maintaining its stable sealing shape; the outer peripheral wall of the second skeleton part 422 is connected to the bushing assembly 20; the connection between the second skeleton part 422 and the bushing assembly 20 ensures... The absolute position of the entire sealing assembly 40 within the bushing is stable, preventing loosening or movement that may occur under high-speed rotation or vibration conditions, thus providing a solid foundation for the sealing function. The inner peripheral wall of the second skeleton part 422 is connected to another part of the sealing unit 41. This allows the skeleton unit 42 to "clamp" and support the soft sealing assembly 40 from both the inside and outside. This one-piece molded skeleton structure with clearly defined functional zones integrates the first skeleton part 421 and the second skeleton part 422 into a robust whole, providing full-circumference, dead-angle-free rigid support for the sealing unit 41. This greatly enhances the overall structural rigidity and shape retention of the sealing assembly 40, effectively avoiding sealing failure caused by plastic deformation. This design constitutes a sealing system that combines rigidity and flexibility, is precisely positioned, and has functional zones, significantly improving the reliability and durability of the seal.

[0044] In this embodiment, as Figure 4As shown, the second dustproof unit 52 includes an integrally formed main body 521 and a protrusion 522; the main body 521 connects the first dustproof unit 51 and the third dustproof unit 53 along the axial direction of the journal unit 12; the main body 521 serves as the core bridge connecting the two ends of the dustproof assembly 50, stably transmitting the axial preload generated by the interference fit between the third dustproof unit 53 and the journal unit 12 to the first dustproof unit 51, which is key to achieving the synergistic effect of the entire dustproof assembly 50; the protrusion 522 extends along the main body 521 towards... The axial extension near the journal unit 12; wherein, the protrusion 522 has an inclined first protruding inner wall 5221 and a second protruding inner wall 5222, and the first protruding inner wall 5221 and the second protruding inner wall 5222 form an acute angle toward the axis of the journal unit 12; this unique acute angle V-shaped structure firstly plays a good reinforcing role in mechanics, greatly enhancing the bending deformation resistance of the protrusion 522 and even the entire second dustproof unit 52, ensuring that it can maintain shape stability when subjected to preload and external interference. Secondly, the two inclined inner walls create conditions for achieving differentiated fit relationships; the inner peripheral wall of the main body 521 and the first protruding inner wall 5221 are fitted with the outer peripheral wall of the first skeleton part 421 with a clearance; achieving frictionless isolation with the sealing assembly 40; the second protruding inner wall 5222 abuts against the bushing assembly 20, which can prevent dust from entering, and at the same time, the second protruding inner wall 5222 can serve as an intermediate support point, providing a crucial intermediate support point for the entire dustproof assembly 50. It enables the pre-tightening force generated by the third dustproof unit 53 to be effectively transmitted and distributed, ensuring that the process of optimizing the gap of the first dustproof unit 51 is more stable and controllable.

[0045] The dustproof component 50 is in the shape of a straight line. When the Shore hardness of the dustproof component 50 is 70-80, the dustproof component 50 is not easy to bend or deform during installation. It has a simple structure and low cost.

[0046] The straight dustproof component 50 has no steel ring. The side opening of the third dustproof unit 53 that abuts against the cross shaft unit 11 needs to be designed with a guide chamfer, the length of which is, for example, about 1 mm. The straight section that mates with the shoulder of the cross shaft unit 11 is relatively long, for example, more than 2 mm. When the ratio of the length of the straight section to the chamfer is greater than 2, it can effectively improve the firmness and sealing of the fit with the shoulder of the cross shaft unit 11. In this invention, no specific limit is made on the size of the chamfer and the straight section, and the actual application shall prevail.

[0047] In this embodiment, as Figure 3As shown, the bushing assembly 20 includes a bushing unit 21; the bushing unit 21 is sleeved on the journal unit 12, and the bushing unit 21 has an interconnected mounting groove 22 and a chamfered groove 23 along the circumference of the journal unit 12; the first dustproof unit 51 is clearance-fitted with the bushing assembly 20 in the mounting groove 22; the mounting groove 22 provides a precise radial positioning and accommodating space for the end of the first dustproof unit 51. This fit ensures that the first dustproof unit 51 is effectively constrained in the axial direction, while maintaining an appropriate movement clearance in its circumference, so that when the clearance optimization sealing effect brought about by the interference fit of the third dustproof unit 53 is achieved, smooth rotation can be maintained and jamming is avoided; the protrusion 522 extends into the chamfered groove 23; the protrusion 522 of the second dustproof unit 52 can deeply... Embedded within the structure of the bushing assembly 20, this "embedded" design greatly optimizes the structural compactness and allows the second dustproof unit 52 to be closer to the internal rolling assembly 30 and sealing assembly 40, thereby more effectively establishing a barrier against the intrusion of external foreign objects. The second protruding inner wall 5222 at least partially abuts against the bushing assembly 20 within the chamfered groove 23. The chamfered groove 23 provides a stable and reliable inclined support platform for the second protruding inner wall 5222, establishing a clear intermediate support point for the second dustproof unit 52. This allows the preload from the third dustproof unit 53 to be effectively transmitted and distributed through the main body 521 and this abutment point, ultimately guiding the clearance fit between the first dustproof unit 51 and the mounting groove 22 to achieve a better sealing state. At the same time, this inclined contact also helps to disperse contact stress and improve the durability of the structure.

[0048] In this embodiment, as Figure 4As shown, the thickness of the first dustproof unit 51 is less than the thickness of the third dustproof unit 53. The third dustproof unit 53 needs to axially abut against the cross shaft unit 11 and achieve an interference fit with the journal unit 12, which exposes it to significant radial clamping force and axial contact stress. Therefore, increasing the thickness of the third dustproof unit 53 can significantly enhance its structural rigidity and strength, ensuring that it can maintain shape stability in the rigid fit with the cross shaft and journal, providing durable and reliable sealing pressure, and preventing sealing failure due to plastic deformation or wear. The task of the first dustproof unit 51 is to form a clearance fit with the bushing assembly 20, and it needs to achieve adaptive adjustment of the clearance under the pre-tightening force of the third dustproof unit 53. Reducing the thickness of the first dustproof unit 51 to make its wall thickness thinner and its flexibility better brings two key benefits: First, it gives the first dustproof unit 51 better elastic deformation capability, enabling it to respond more sensitively to the pre-tightening force transmitted by the third dustproof unit 53, thereby more effectively reducing the fit clearance between it and the bushing assembly 20 and improving the dynamic sealing effect; Second, the excellent flexibility also ensures that it can maintain a smooth fit with the bushing during the operation of the universal joint, avoiding additional frictional resistance or wear due to excessive rigidity. In summary, this "different thickness" design allows the two ends of the dustproof assembly 50 to perform their respective functions, combining the reliable rigid sealing of the third dustproof unit 53 with the flexible dynamic sealing of the first dustproof unit 51, thus improving the overall performance.

[0049] In this embodiment, as Figure 3 As shown, a groove 54 is formed on the outer peripheral wall of the first dustproof unit 51; this is equivalent to artificially creating a structurally weak area or flexible hinge in the circumferential direction of the first dustproof unit 51. This greatly enhances the radial elastic deformation capability of the first dustproof unit 51, making it more flexible. When the third dustproof unit 53 is interference-fitted with the journal unit 12 and applies axial preload to the entire dustproof assembly 50, this more elastic first dustproof unit 51 can more sensitively and significantly contract radially, thereby more effectively reducing the actual clearance between it and the bushing assembly 20, dynamically improving the sealing tightness at this point. At the same time, this flexible optimization achieved through structural design avoids the strength risks associated with further thinning of the overall wall thickness, that is, while improving sealing sensitivity, the necessary structural integrity of the first dustproof unit 51 is still maintained. Ultimately, the groove 54 ensures that the first dustproof unit 51 can achieve a better dynamic sealing effect with lower frictional resistance, further preventing foreign matter intrusion and extending service life.

[0050] In this embodiment, as Figure 3As shown, the clearance between the first dustproof unit 51 and the bushing assembly 20 in the mounting groove 22 is greater than or equal to the clearance between the inner peripheral wall of the main body 521 and the outer peripheral wall of the first protruding inner wall 5221 and the first skeleton part 421. This allows the axial preload generated by the interference fit between the third dustproof unit 53 and the journal unit 12 to be more effectively converted into radial displacement of the first dustproof unit 51, driving it to move closer to the bushing assembly 20, thereby achieving adaptive reduction of the clearance and optimizing dynamic sealing. At the same time, the smaller (or equal) clearance between the main body 521 and the first protruding inner wall 5221 and the first skeleton part 421 is primarily intended to ensure that the dustproof assembly 50 and the sealing assembly 40, which serves as the main seal, always maintain a defined and safe operating distance. This design precisely prevents the main body 521 or protrusion 522 of the dustproof assembly 50 from contacting or interfering with the first skeleton 421 when the dustproof assembly 50 deforms under preload or external force, thus completely eliminating the possibility of frictional wear between them. By setting the gap on the dustproof side to be greater than or equal to the gap on the sealing side, a clear "anti-interference" priority is established, that is, under any operating condition, priority is given to ensuring that the working environment of the main sealing assembly 40 is not disturbed, thereby achieving highly reliable operation of the dustproof function and the sealing function in a coordinated yet non-interfering manner.

[0051] In this embodiment, as Figure 2As shown, the journal unit 12 includes a first journal 121 and a second journal 122 connected sequentially along the same axis; the circumference of the first journal 121 is greater than the circumference of the second journal 122; the third dustproof unit 53 abuts against the cross shaft unit 11 along the axial direction of the journal unit 12 and at least partially interferes with the first journal 121 along the circumferential direction of the journal unit 12; the first journal 121 has a larger circumference, which provides a wider and more stable mating surface for the third dustproof unit 53, which not only makes the interference fit connection more reliable and durable, but also ensures dustproof protection. The robust mounting of component 50 on journal unit 12, combined with a larger contact area, disperses contact stress, significantly improving the radial sealing effect and structural stability of this critical interface and effectively preventing contaminants from entering from the cross shaft end. Sealing unit 41 is fitted onto the outer peripheral wall of the second journal 122. Placing sealing unit 41 on the smaller-circumference second journal 122 offers several advantages: First, it provides an independent, protected mounting area for sealing unit 41, ensuring its installation and function do not interfere with those of the third dustproof unit 53, achieving functional zoning. Second, the smaller mating circumference effectively reduces sliding friction and wear of the sealing lip while maintaining the same sealing contact pressure, thus reducing the universal joint's transmission resistance and extending the service life of sealing unit 41. In summary, this stepped journal design cleverly utilizes structural differences to simultaneously optimize the static sealing reliability of the third dustproof unit 53 and the dynamic sealing performance of sealing unit 41, jointly improving the overall efficiency and durability of the universal joint.

[0052] Example 2:

[0053] In this embodiment, the present invention also provides an installation method for a universal joint dustproof structure, comprising the following steps:

[0054] S10, the rolling assembly 30 is installed inside the bushing assembly 20;

[0055] S20, the sealing assembly 40 is installed inside the bushing assembly 20 to initially seal the rolling assembly 30;

[0056] S30, the dustproof component 50 is installed on the bushing assembly 20 and the sealing component 40 to form a mounting cavity;

[0057] S40, the cross shaft assembly 10 is installed into the mounting cavity; wherein, the first dustproof unit 51 is clearance-fitted with the bushing assembly 20; the third dustproof unit 53 abuts against the cross shaft unit 11 and is interference-fitted with the journal unit 12; a portion of the second dustproof unit 52 is clearance-fitted with the sealing assembly 40, and at least a portion of the second dustproof unit 52 abuts against the bushing assembly 20; wherein, the dustproof assembly 50 includes an integrally formed first dustproof unit 51, second dustproof unit 52 and third dustproof unit 53; the two ends of the second dustproof unit 52 are respectively connected to the first dustproof unit 51 and the third dustproof unit 53.

[0058] First, the rolling assembly 30 is installed inside the bushing assembly 20, providing the foundation for the entire transmission core. Next, the sealing assembly 40 is installed inside the bushing assembly 20 to initially seal the rolling assembly 30. This step, before installing the cross shaft assembly 10, establishes a primary sealing barrier inside the bushing, effectively preventing contaminants that may be introduced during subsequent installation from directly contacting the rolling assembly 30, while also initially sealing in lubricating grease. Then, the dustproof assembly 50 is installed on the bushing assembly 20 and the sealing assembly 40, forming an installation cavity. The dustproof assembly 50... The system includes a first dustproof unit 51, a second dustproof unit 52, and a third dustproof unit 53, all integrally formed. The two ends of the second dustproof unit 52 are connected to the first dustproof unit 51 and the third dustproof unit 53, respectively. This step installs the dustproof assembly 50 as a whole. Its integrated structure avoids the complexity of separate installation and the risk of misalignment, ensuring its structural integrity. At this point, it and the already positioned components together form an installation cavity, preparing for the subsequent installation of the cross shaft assembly 10. Finally, the cross shaft assembly 10 is installed into the installation cavity. This final step achieves crucial functional fits: the first dustproof unit 51 has a clearance fit with the bushing assembly 20, providing a foundation for dynamic rotation; the third dustproof unit 53 abuts against the cross shaft unit 11 and has an interference fit with the journal unit 12. This interference fit not only achieves static sealing in the axial and radial directions but also applies a preload to the overall dustproof assembly 50. Under this preload, combined with the intermediate support provided by the abutment of part of the second dustproof unit 52 with the bushing assembly 20, the clearance between the first dustproof unit 51 and the bushing assembly 20 is adaptively optimized and reduced. Simultaneously, the clearance fit between part of the second dustproof unit 52 and the sealing assembly 40 ensures no frictional interference between the external dustproof and internal main seals, allowing each to work independently and efficiently. The entire installation method is interconnected, ultimately constructing a reliable dustproof structure with multiple seals and coordinated operation.

[0059] Those skilled in the art will understand that the above embodiments are specific examples of implementing the present invention, and in practical applications, various changes can be made in form and detail without departing from the scope of the present invention.

Claims

1. A universal joint dustproof structure, characterized in that, The universal joint dustproof structure includes: A cross shaft assembly includes a cross shaft unit and a journal unit connected to the cross shaft unit; A bushing assembly is fitted onto the outer peripheral wall of the journal unit; A dustproof assembly includes a first dustproof unit, a second dustproof unit, and a third dustproof unit integrally formed sequentially along the axial direction of the journal unit; the inner peripheral walls of the first and second dustproof units, together with the outer peripheral wall of the journal unit and the inner peripheral wall of the bushing assembly, form a receiving cavity; the first dustproof unit is sleeved on the outer peripheral wall of the bushing assembly and has a clearance fit with the bushing assembly; the third dustproof unit is sleeved on the outer peripheral wall of the journal unit; the third dustproof unit abuts against the cross shaft unit along the axial direction of the journal unit and has an interference fit with the journal unit along the circumferential direction of the journal unit; A rolling assembly is located within the receiving cavity; the rolling assembly is rotatably disposed between the journal unit and the bushing assembly. A sealing assembly is located within the receiving cavity; the sealing assembly is sleeved on the outer peripheral wall of the journal unit; wherein, the second dustproof unit is clearance-fitted with the sealing assembly; a portion of the second dustproof unit abuts against the bushing assembly.

2. The universal joint dustproof structure according to claim 1, characterized in that, The sealing assembly includes a sealing unit and a skeleton unit; the sealing unit is sleeved on the outer peripheral wall of the journal unit; the inner peripheral wall of the skeleton unit is connected to the sealing unit along the circumferential direction of the journal unit; a portion of the outer peripheral wall of the skeleton unit is connected to the bushing assembly along the circumferential direction of the journal unit; another portion of the outer peripheral wall of the skeleton unit is clearance-fitted with the second dustproof unit along the circumferential direction of the journal unit.

3. The universal joint dustproof structure according to claim 2, characterized in that, The skeleton unit includes an integrally formed first skeleton part and a second skeleton part; the outer peripheral wall of the first skeleton part is clearance-fitted with a portion of the second dustproof unit; the inner peripheral wall of the first skeleton part is connected to a portion of the sealing unit; the outer peripheral wall of the second skeleton part is connected to the bushing assembly; and the inner peripheral wall of the second skeleton part is connected to another portion of the sealing unit.

4. The universal joint dustproof structure according to claim 3, characterized in that, The second dustproof unit includes an integrally formed main body and a protrusion; the main body is connected to the first dustproof unit and the third dustproof unit along the axial direction of the journal unit; the protrusion extends along the main body towards the journal unit; wherein the protrusion has an inclined first protruding inner wall and a second protruding inner wall, and the first protruding inner wall and the second protruding inner wall form an acute angle towards the axial direction of the journal unit; the inner peripheral wall of the main body and the first protruding inner wall are clearance-fitted with the outer peripheral wall of the first skeleton part; the second protruding inner wall abuts against the bushing assembly.

5. A universal joint dustproof structure according to claim 4, characterized in that, The bushing assembly includes a bushing unit; the bushing unit is sleeved on the journal unit, and the bushing unit has an interconnected mounting groove and a chamfered groove along the circumference of the journal unit; the first dustproof unit is clearance-fitted with the bushing assembly in the mounting groove; the protrusion extends into the chamfered groove; the inner wall of the second protrusion at least partially abuts against the bushing assembly in the chamfered groove.

6. The universal joint dustproof structure according to claim 1, characterized in that, The thickness of the first dustproof unit is less than the thickness of the third dustproof unit.

7. A universal joint dustproof structure according to claim 6, characterized in that, The outer peripheral wall of the first dustproof unit has a groove.

8. A universal joint dustproof structure according to claim 5, characterized in that, The clearance between the first dustproof unit and the bushing assembly in the mounting groove is greater than or equal to the clearance between the inner peripheral wall of the main body and the outer peripheral wall of the first protruding inner wall.

9. A universal joint dustproof structure according to claim 2, characterized in that, The journal unit includes a first journal and a second journal connected in sequence along the same axis; the circumference of the first journal is greater than the circumference of the second journal; the third dustproof unit abuts against the cross shaft unit along the axial direction of the journal unit and is at least partially press-fitted with the first journal along the circumferential direction of the journal unit; the sealing unit is sleeved on the outer peripheral wall of the second journal.

10. A method for installing a universal joint dustproof structure, wherein the method for installing the universal joint dustproof structure is applied to the universal joint dustproof structure according to any one of claims 1-9, characterized in that, The installation method of the universal joint dustproof structure includes: The rolling component is installed inside the bushing assembly; The sealing assembly is installed inside the bushing assembly to initially seal the rolling assembly; The dustproof component is installed on the bushing assembly and the sealing component to form a mounting cavity; The cross shaft assembly is installed into the mounting cavity; wherein, the first dustproof unit is clearance-fitted with the bushing assembly; the third dustproof unit abuts against the cross shaft unit and is interference-fitted with the journal unit; a portion of the second dustproof unit is clearance-fitted with the sealing assembly, and at least a portion of the second dustproof unit abuts against the bushing assembly; wherein, the dustproof assembly includes an integrally formed first dustproof unit, second dustproof unit, and third dustproof unit; the two ends of the second dustproof unit are respectively connected to the first dustproof unit and the third dustproof unit.

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